We intend to initiate a series of studies to study biological and behavioral factors implicated in the etiology of sustained hypertension in adolescents. We hypothesize that ventricular hypertrophy, cardiovascular response to environmental stimuli, and the Type A (Coronay Prone) Behavior Pattern are primary in promoting hypertension in this population. Black and white males 14 to 16 years of age will be selected from the following groups; (a) hypertensive with left ventricular hypertrophy (10 subjects), (b) hypertensive without left ventriculary hypertrophy (10 subjects), and (c) normotensive without left ventriuclar hypertrophy. All will be assessed for the coronary prone behavior pattern. Subjects will be tested in Small Group Programmed Environment Laboratory in Phipps Psychiatric Clinic at Johns Hopkins. Each subject will be exposed to alternating 20 minute phases of (a) baseline-quiet resting; (b) metronome-conditioned relaxation; and (c) responding to the Alluisi Multiple Task Performance Battery. Phase sequence will be counterbalanced across subjects in order to control for order effects. Dependent measures will be (1) mean systolic and diastolic blood pressure, heart rate, pulse transit time, and peripheral vasoconstriction decreases from resting to relaxation, from resting to task performance, and from relaxation to task performance. Analyses of variance, multiple regression analysis, and path analysis will be used to chart relationships between ventricular hypertropy, hypertension, and the coronary prone behavior pattern. We predict that hypertensive subjects will show greater cardiovascular response than normotensive subjects, that Type A subjects will show greater cardiovascular response than Type B subjects, and that subjects with left ventricular hyprtrophy will show less cardiovascular response than non-left ventricular hypertrophy hypertensives. These data will asssist us in preparing a larger research project to track adolescents over time to build a model of factors related to the etiology and maintenance of elevated blood pressure in adoloscents.